1. Field of the Invention
The present invention relates to a directional antenna and radiating pattern adjustment method, and more particularly, to a directional antenna and radiating pattern adjustment method increasing antenna gain by adding a reflector.
2. Description of the Prior Art
An electronic product with a wireless communication function, such as a laptop computer, a personal digital assistant (PDA) and soon, transmits or receives radio signals through an antenna to access a wireless network. Therefore, for facilitating the wireless network access, an ideal antenna should have a wide bandwidth and a small size to meet the trends of compact electronic products.
A highly directional antenna such as a Yagi-Uda antenna achieves high gain over a rather narrow band. As a result, multiple Yagi-Uda antennas are commonly utilized in a wireless communication system supporting multi-in multi-out (MIMO) technology or a beam switchable antenna system. With a proper arrangement of the multiple Yagi-Uda antennas, the wireless communication system can reach high data throughput and significantly increase transmission distance under limited bandwidth or power expenditure.
In order to reach better performance of the Yagi-Uda antenna, a conventional method is to add directors to the Yagi-Uda antenna, which can direct a current route in a radiator of the Yagi-Uda antenna. In such a situation, directivity and antenna gain of the Yagi-Uda antenna increase. However, antenna body and the area of the Yagi-Uda antenna also increase.
In order to meet the trends of compact electronic products, there is a need to increase antenna gain and directivity of the Yagi-Uda antenna without increasing antenna area.